<!DOCTYPE html>
<link rel="help" src="https://drafts.csswg.org/scroll-animations-1/#scroll-timeline-at-rule">
<link rel="help" src="https://drafts.csswg.org/scroll-animations-1/#descdef-scroll-timeline-source">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/web-animations/testcommon.js"></script>
<style>
  :root {
    height: 100vh;
    overflow: scroll;
  }
  body {
    height: 200vh;
  }
  .scroller {
    overflow: scroll;
    width: 100px;
    height: 100px;
  }
  #boxless {
    display: none;
  }
  .contents {
    height: 300px;
  }
  @keyframes expand {
    from { width: 100px; }
    to { width: 200px; }
  }
  @scroll-timeline timeline_source_none {
    source: none;
    time-range: 10s;
    start: 0px;
    end: 100px;
  }
  @scroll-timeline timeline_source_auto {
    source: auto;
    time-range: 10s;
    start: 0px;
    end: 100px;
  }
  @scroll-timeline timeline_source_selector {
    source: selector(#scroller);
    time-range: 10s;
    start: 0px;
    end: 100px;
  }
  @scroll-timeline timeline_source_unspecified {
    time-range: 10s;
    start: 0px;
    end: 100px;
  }
  @scroll-timeline timeline_source_nonexistent_id {
    source: selector(#doesnotexist);
    time-range: 10s;
    start: 0px;
    end: 100px;
  }
  @scroll-timeline timeline_source_no_layout_box {
    source: selector(#boxless);
    time-range: 10s;
    start: 0px;
    end: 100px;
  }
  #container > div {
    width: 0px;
    animation-name: expand;
    animation-duration: 10s;
    animation-timing-function: linear;
  }
  /* Ensure stable expectations if feature is not supported */
  @supports not (animation-timeline:foo) {
    #container > div { animation-play-state: paused; }
  }
  #element_source_none { animation-timeline: timeline_source_none; }
  #element_source_auto { animation-timeline: timeline_source_auto; }
  #element_source_unspecified { animation-timeline: timeline_source_unspecified; }
  #element_source_selector { animation-timeline: timeline_source_selector; }
  #element_source_nonexistent_id { animation-timeline: timeline_source_nonexistent_id; }
  #element_source_no_layout_box { animation-timeline: timeline_source_no_layout_box; }
</style>
<body>
  <div class=scroller id=scroller>
    <div class=contents></div>
  </div>
  <div class=scroller id=boxless>
    <div class=contents></div>
  </div>
  <div id=container>
    <div id=element_source_none></div>
    <div id=element_source_auto></div>
    <div id=element_source_unspecified></div>
    <div id=element_source_selector></div>
    <div id=element_source_nonexistent_id></div>
    <div id=element_source_no_layout_box></div>
  </div>
  <script>
    // Set progress of animations linked to #scroller to 75%.
    scroller.scrollTop = 75;
    // Set progress of animations linked to document.scrollingElement to 25%.
    document.scrollingElement.scrollTop = 25;

    promise_test(async (t) => {
      await waitForNextFrame();
      assert_equals(getComputedStyle(element_source_none).width, '0px');
    }, 'Source none causes inactive timeline');

    promise_test(async (t) => {
      await waitForNextFrame();
      assert_equals(getComputedStyle(element_source_auto).width, '125px');
    }, 'Source auto selects scrollingElement of the document');

    promise_test(async (t) => {
      await waitForNextFrame();
      assert_equals(getComputedStyle(element_source_unspecified).width, '125px');
    }, 'Unspecified source behaves like auto');

    promise_test(async (t) => {
      await waitForNextFrame();
      assert_equals(getComputedStyle(element_source_selector).width, '175px');
    }, 'Source selector(<id-selector>) selects an element');

    promise_test(async (t) => {
      await waitForNextFrame();
      assert_equals(getComputedStyle(element_source_nonexistent_id).width, '0px');
    }, 'Unknown source causes inactive timeline');

    promise_test(async (t) => {
      await waitForNextFrame();
      assert_equals(getComputedStyle(element_source_no_layout_box).width, '0px');
    }, 'Source with no layout box causes inactive timeline');

    // TODO(https://github.com/w3c/csswg-drafts/issues/5289): Add tests for
    // sources that change when behavior is clarified.

  </script>
</body>
